1. Field of the Invention
The present invention relates to a wireless sensor network system and a clustering method thereof. More particularly, the present invention relates to a wireless sensor network system including a plurality of clusters and a cluster management method thereof.
2. Description of the Related Art
A wireless sensor network typically includes a plurality of clusters and a sink node for collecting sensing data from each cluster. Each cluster comprises a cluster head including one sensor node selected from a plurality of sensor nodes, and the remaining sensor nodes. In operation, the cluster head of a cluster aggregates sensing data received from each of the sensor nodes of the cluster and transfers the aggregated sensing data to the sink node. Presently, the cluster head is powered by a battery, and there is a significant amount of difficulty to replace and/or recharge the battery. In view of this difficulty, an energy consumption level of the cluster head may be an important parameter that determines the lifetime of the wireless sensor network.
However, the above-described wireless sensor network has a problem in that the cluster head consumes a large amount of energy for data aggregation. The problem regarding energy consumption becomes more serious as the number of sensor nodes included in a cluster increases. Another problem with the above-described wireless sensor network is that sensor node management efficiency is degraded when the number of sensor nodes included in the cluster is excessively small. Consequently, a need exists for a cluster management method capable of properly maintaining the number of sensor nodes included in a cluster.